Peripheral Nerve Stimulation (“PNS”) therapies, such as Vagus Nerve Stimulation (“VNS”), are promising treatments for many chronic diseases including epilepsy and depression. Traditional stimulation frequency is in the range of a few tens of hertz to a few hundreds of hertz. Higher stimulation frequency in kHz range, e.g. from 1 kHz to 50 kHz, may benefit for some diseases. Safety is one of the most important consideration for neuromodulation, thus there is a need for systems and methods for active charge balancing.